If he is using one 125jet and splitting it in to four lines (one per cylinder) that is 31.25 hp to each.
I am running four 20 jets and that give me a total of 63 more hp.He sould be getting a total of 126.2 hp give or take a couple hp.So if his bike makes lets say 155 hp stock and a added 126 hp that makes a total of 281 hp not good with out more gas.